In 2015, five major randomized controlled trials showed that thrombectomy for anterior large vessel ischemic strokes within 6 hours provided benefit. What about patients who present beyond 6 hours? The DAWN a multicenter, prospective, randomized, open-label, blinded endpoint trial was designed to study thrombectomy in stroke patients who present within 6-24 hours, have a small MRI or CT perfusion core and clinical deficit out of proportion to imaging. Key inclusion criteria were: last known well 6-24 hours, mismatched clinical deficit and infarct defined in 3 groups (Group A: age >80, NIHSS >10, infarct volume <21; Group B: age <80, NIHSS >10, infarct volume <31 and Group C: age <80, NIHSS >20, infarct volume 31-51) and CT or MR angiogram evidence of ICA terminus and/or M1 occlusion. Eligible patients were randomized 1:1 to thrombectomy plus standard medical care or to standard medical care alone. Only 1 stent-retriever was permitted and rescue reperfusion therapy with other devices was not allowed. The trial was stopped prematurely at 31 months for superiority of thrombectomy. Both endpoints favored thrombectomy: 1) mean mRS disability score (0=death, 10=no symptoms) at 90 days was 5.5 vs 3.4; 2) functional independence rate (mRS of 0-2) at 90 days was 49% vs 13%. All secondary endpoints also favored thrombectomy and safety was similar. Overall, this study suggests that for every 2.8 patients who underwent thrombectomy 1 additional patient had functional independence at 90 days.
New England Journal of Medecine